Sand control tools and methods for vertical wells

Abstract

The application provides a three-dimensional well sand prevention tool and method, which comprises a flexible outer pipe and a flexible inner pipe; the flexible outer pipe comprises a plurality of connecting nipples and screen pipe nipples, the connecting nipples are connected through a universal force transmission structure, the screen pipe nipples are connected through the universal force transmission structure, and the connecting nipples and the screen pipe nipples are connected through the universal force transmission structure; the universal force transmission structure is used for transmitting torque or axial force; the flexible inner pipe is inserted into the flexible outer pipe, and an intermediate annular space is formed between the flexible outer pipe and the flexible inner pipe; the rear part of the flexible inner pipe extends to the rear of the rearmost screen pipe nipple; gravel can be filled in an annular space formed between the flexible outer pipe and a well wall, so that the technical problem that effective sand prevention is difficult to realize in an extremely short radius branch wellbore is solved, and the three-dimensional well sand prevention tool and method are formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas drilling, in particular to a kind of three-dimensional well sand control tool and method. BACKGROUND

[0002] For very short radius branch wellbore, its interior usually cannot adopt gravel packing sand control, segmented sand control and other means, therefore, it is difficult to achieve effective sand control. SUMMARY

[0003] The present application aims to provide a kind of three-dimensional well sand control tool and method, that is, by solving the gravel packing problem of ultra-short radius well with turning radius less than 30 meters, the sand control of three-dimensional well is realized. Especially in the completion of very short radius branch wellbore with turning radius less than 10 meters, it can achieve unexpected effect.

[0004] The above-mentioned purpose of the present application can be realized by using the following technical scheme:

[0005] The present application provides a kind of three-dimensional well sand control tool, comprising: flexible outer tube and flexible inner tube;The flexible outer tube includes a plurality of connecting short sections and screen pipe short sections, or the flexible outer tube includes a plurality of screen pipe short sections;Connecting short section, screen pipe short section and connecting short section and screen pipe short section are connected by universal force transmission structure, and the universal force transmission structure is used to transmit torque or axial force;The flexible inner tube is inserted into the flexible outer tube, and the upper part of the flexible inner tube is sealingly connected with the flexible outer tube, and the intermediate annulus is formed between the flexible outer tube and the flexible inner tube;The rear part of the flexible inner tube extends to the rear of the screen pipe short section at the back;The flexible inner tube adopts composite material pipe, high plasticity metal pipe, wire mesh rubber tube or armored pipe;Gravel can be filled in the annular space formed between the flexible outer tube and the well wall.

[0006] In the preferred embodiment, the flexible inner tube adopts composite material pipe, high plasticity metal pipe, wire mesh rubber tube or armored pipe;The length of the screen pipe short section is 1-15 times of its outer diameter, and the universal force transmission structure includes torque transmission member and ball joint.

[0007] In the preferred embodiment, the pipe wall of the flexible inner tube is provided with pipe wall through structure, and the pipe wall through structure is provided with soluble sealing plug, and the soluble sealing plug can seal the pipe wall through structure on the pipe wall of the flexible inner tube.

[0008] In the preferred embodiment, the difference between the external pressure and the internal pressure that can be borne by the whole formed by the pipe body of the flexible inner tube and the soluble sealing plug is greater than 0.1 MPa.

[0009] In a preferred embodiment, the soluble sealing plug is made of soluble material, and the soluble material has a dissolving time of 10-1000 hours.

[0010] In a preferred embodiment, the cooperating clearance of the universal force transmission structure is smaller than the screen pipe joint's screen size, or the universal force transmission structure comprises a sealing plug.

[0011] In a preferred embodiment, the flexible inner tube's front part is provided with a first one-way valve, and the two ends of the first one-way valve are respectively connected with the flexible inner tube's interior and the flexible outer tube's exterior, and the flow direction of the first one-way valve is from the flexible inner tube's interior to the annulus between the flexible outer tube and the well wall.

[0012] In a preferred embodiment, the flexible inner tube's front part is provided with a second one-way valve, and the two ends of the second one-way valve are respectively connected with the flexible inner tube's interior and the intermediate annulus, and the flow direction of the second one-way valve is from the intermediate annulus to the flexible inner tube's interior.

[0013] In a preferred embodiment, the flexible outer tube's tube wall is provided with a filling hole, and the flexible outer tube's rear end is provided with a top suspension device, and the top suspension device is used for hanging the flexible outer tube with the main wellbore casing's inner wall or the branch well's window, and the filling hole is arranged in front of the top suspension device, and the filling hole is used for injecting filling material into the annulus between the screen pipe joint and the well wall.

[0014] The present application provides a three-dimensional well sand prevention method, which adopts the three-dimensional well sand prevention tool, and the three-dimensional well sand prevention method comprises the following steps:

[0015] The filling material-containing fluid flows from the rear to the front through the annulus between the flexible outer tube and the well wall;

[0016] After the fluid is filtered by the screen pipe joint, the fluid enters the flexible inner tube through the flexible inner tube's front end, and the fluid flows from the front to the rear in the flexible inner tube's interior;

[0017] After the filling is completed, the soluble sealing plug on the flexible inner tube's tube wall reaches the dissolving time, and the dissolving time of the soluble sealing plug is 10-1000 hours.

[0018] The present application has the following characteristics and advantages:

[0019] The three-dimensional well sand control tool provided by this invention forms an intermediate annulus between the flexible inner and outer tubes through a nested method of flexible outer and inner tubes. This annulus can be used for gravel packing or for segmented development using gravel with different porosities and bonding properties. It achieves ultra-short radius gravel packing completion, which, compared to existing ultra-short radius screen completion technology, effectively increases the drainage area and reduces flow resistance. It has particular advantages for unconventional reservoirs such as heavy oil and hydrates.

[0020] The three-dimensional well sand control tool provided by this invention can achieve three-dimensional well network completion, utilizing the casing window inside the reservoir to achieve radial extension of gravel backfill. Especially in heavy oil development, the casing can achieve excellent sealing, and the reservoir is located at the window. The flexible gravel backfill completion string extending radially from the window can significantly increase the reservoir exposure area, which can have a good effect on steam injection and oil production. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 An overall diagram of a three-dimensional well sand control tool provided by the present invention;

[0023] Figure 2 A partial view of a short section of a screen pipe for a three-dimensional well sand control tool provided by the present invention;

[0024] Figure 3 A partial view of the filling part of a three-dimensional well sand control tool provided by the present invention;

[0025] Figure 4 A flowchart illustrating the filling process of the three-dimensional well sand control tool provided by this invention;

[0026] Figure 5 A partial flow chart of the filling process of the three-dimensional well sand control tool provided by the present invention;

[0027] Figure 6 The production process flow chart of the three-dimensional well sand control tool provided by the present invention;

[0028] Figure 7 A schematic diagram of one embodiment of the three-dimensional well sand control tool provided by the present invention;

[0029] Figure 8 for Figure 7 A magnified view of a section at point D;

[0030] Figure 9 A schematic diagram of another embodiment of the three-dimensional well sand control tool provided by the present invention.

[0031] Explanation of icon numbers:

[0032] 1. Flexible outer tube; 11. Connecting short section; 12. Screen tube short section;

[0033] 14. Universal force transmission structure; 141. Ball joint; 142. Ball seat; 143. Torque transmission component;

[0034] 33. Intermediate annulus; 34. Filling hole;

[0035] 2. Flexible inner tube; 21. Through-wall structure; 22. Soluble sealing plug;

[0036] 31. First check valve; 32. Second check valve;

[0037] 36. Flow channel converter;

[0038] 37. Drill pipe;

[0039] 38. Screen module;

[0040] 39. Service column;

[0041] 51. Top packer; 52. Top suspension device. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] Option 1

[0044] This invention provides a three-dimensional well sand control tool, such as... Figures 1-9 As shown, it includes a flexible outer tube 1 and a flexible inner tube 2; the flexible outer tube includes several connecting short sections 11 and screen tube short sections 12, or the flexible outer tube includes several screen tube short sections; the connecting short sections 11 are connected by a universal force transmission structure 14, the connecting short sections 11 and the screen tube short sections 12 are connected by a universal force transmission structure 14, and the screen tube short sections 12 are connected by a universal force transmission structure 14, the universal force transmission structure 14 is used to transmit torque or axial force; the flexible inner tube 2 is inserted into the flexible outer tube 1, and an intermediate annular space 33 is formed between the flexible outer tube 1 and the flexible inner tube 2; the rear of the flexible inner tube 2 extends to the rear of the last screen tube short section 12, and gravel can fill the annular space formed between the flexible outer tube and the well wall.

[0045] For wells with extremely short radius branches where gravel packing and segmented sand control are ineffective, this invention provides a three-dimensional well sand control tool. Through a nested method of flexible outer and inner tubes, an intermediate annulus 33 is formed between the flexible inner and outer tubes. This annulus 33 can be used for gravel packing or for segmented development using gravels with different porosities and bonding properties. By solving the problem of ultra-short radius gravel packing, three-dimensional well sand control is achieved. Compared with existing ultra-short radius screen completion technology, this significantly extends service life, improves sand control effect, provides better support for the wellbore, and effectively increases the drainage area to reduce flow resistance. It has particular advantages for unconventional reservoirs such as loose sandstone formations, heavy oil, and hydrates.

[0046] The three-dimensional well sand control tool provided by this invention can achieve three-dimensional well network completion, utilizing the casing window inside the reservoir to achieve radial extension of gravel backfill. Especially in heavy oil development, the casing can achieve excellent sealing, and the reservoir is located at the window. The flexible gravel backfill completion string extending radially from the window can significantly increase the reservoir exposure area, which can have a good effect on steam injection and oil production.

[0047] The connecting short sections can be omitted in the flexible outer tube, that is, the flexible outer tube includes several screen tube short sections. In this case, the adjacent screen tube short sections 12 are connected by a universal force transmission structure 14.

[0048] Preferably, the flexible inner tube is made of composite material tube, high plasticity metal tube, metal wire mesh rubber tube or armored tube. Its advantage is that the flexibility of composite material tube, high plasticity metal tube, metal wire mesh rubber tube or armored tube is close to that of flexible outer tube. It can pass through ultra-short radius well sections with a turning radius of less than 30 meters in the form of double tubing, especially extremely short radius well sections with a turning radius of 1-10 meters.

[0049] As a more reasonable technical solution, the flexible inner tube adopts composite material coiled tubing or high-plasticity metal coiled tubing.

[0050] Specifically, the flexible outer tube is generally a flexible outer tube with a turning radius of less than 30 meters, especially a flexible outer tube with a turning radius between 1 and 10 meters; the flexible inner tube is generally a flexible outer tube with a turning radius of less than 30 meters, especially a flexible outer tube with a turning radius between 1 and 10 meters.

[0051] In one embodiment, the screen tube section includes a liner section, a wire-wound screen tube section, a metal foam screen tube section, a metal filament screen tube section, a pre-filled screen tube section, and a section containing a sand filtering device. The length of the screen tube section is 1-15 times its outer diameter.

[0052] The upper part of the flexible inner tube 2 can be sealed to the flexible outer tube 1. The flexible inner tube includes any one or a combination of armored hoses, rubber hoses, composite material tubes, and high-plasticity tubes; specifically, the high-plasticity tube is a high-plasticity metal tube, such as coiled tubing or similar tubing strings.

[0053] In one embodiment, a through-wall structure 21 is provided on the wall of the flexible inner tube, and a soluble sealing plug 22 is provided in the through-wall structure 21 to seal the through-wall structure 21 on the wall of the flexible inner tube.

[0054] During the gravel filling process, the sand-carrying fluid carries gravel or sand through the filling holes into the annular space between the flexible outer casing and the wellbore. After sand removal, the sand-carrying fluid needs to return to the main wellbore from the flexible inner casing. During the gravel filling stage, the soluble sealing plug maintains the integrity of the flexible inner casing, allowing the gravel or sand to flow fully to the front of the flexible outer casing. After the gravel filling operation is completed, the soluble sealing plug dissolves, maintaining the connectivity of the flexible inner casing and fully releasing production capacity.

[0055] The through-wall structure can be any one or a combination of holes, grooves, and slots, where the holes, grooves, and slots penetrate the flexible inner tube wall. A soluble sealing plug 22 is installed within the holes, grooves, and slots to seal the holes, grooves, and slots in the flexible inner tube wall. The soluble sealing plug is supported by a soluble material that can dissolve internally downhole within a pre-designed structure. Figure 2 As shown, the through structure 21 of the pipe wall is a hole, and a soluble sealing plug 22 is provided in the hole to seal the hole in the wall of the flexible inner pipe 2.

[0056] Furthermore, the holes, grooves, and slots on the flexible inner tube wall are evenly distributed on the flexible inner tube wall. The holes, grooves, and slots on the flexible inner tube wall are in a non-dissolving state during the branch well washing and gravel filling. After the filling operation, the soluble sealing plugs dissolve, and the fluid in the formation can flow into the flexible inner tube through the holes, grooves, and slots that penetrate the tube wall, or the fluid in the flexible inner tube can be injected into the formation through the holes, grooves, and slots.

[0057] The flexible inner tube 2, formed by the tube body and the soluble sealing plug 22, is an integral flexible inner tube capable of withstanding external pressure. In one embodiment, the difference between the external pressure and the internal pressure borne by the integral formed by the tube body and the soluble sealing plug 22 is greater than 0.1 MPa.

[0058] The dissolution time of the soluble material in the soluble sealing plug 22 is greater than the sum of the tubing operation time a and the filling time b. In one embodiment, the dissolution time of the soluble material is between 10 and 1000 hours. Preferably, the dissolution time of the soluble material is less than 3 days (48 hours).

[0059] The universal joint 14 can be a universal joint used to transmit torque and axial force. In one embodiment, the universal joint 14 includes a torque transmission element 143 and a ball joint. Figure 2 As shown, the ball joint includes a ball head 141 and a ball seat 142, which can rotate relative to each other. A torque transmission element 143 is provided between the ball head 141 and the ball seat 142. The torque transmission element can be a keyway, a ball, or a pin, such as a torque transmission pin or a steel ball. The torque transmission element can also be other components used for torque transmission in ball joints in the prior art, and is not limited here.

[0060] Furthermore, the fitting clearance of the universal force transmission structure 14 is smaller than the sieving size of the screen tube short section, or the universal force transmission structure includes a seal to ensure the filtration effect and prevent formation sand from entering the intermediate annulus without passing through the screen tube short section.

[0061] Specifically, a screen, screen slits, or screen gaps can be installed on the screen tube short section to achieve filtration. The sieving size is controlled by the structure of the screen, screen slits, or screen gaps. Correspondingly, the fitting clearance of the universal force transmission structure 14 is smaller than the screen diameter, the width of the screen slit, or the width of the screen gap to ensure filtration effect and prevent formation sand from entering the intermediate annulus without passing through the screen tube short section. The screen installed on the screen tube short section can also include screen cloth, metal foam, or screen module 38. The fitting clearance of the universal force transmission structure 14 mainly refers to the gap between the ball head 141 and the ball seat 142.

[0062] By setting a sealing ring or sealing ring between the ball head 141 and the ball seat 142, pressure leakage from the gaps in the various short sections can be prevented during circulating well washing and gravel packing. Larger particles can also be prevented from passing through the universal force transmission structure 14. The seal can be a sealing ring or sealing ring, and the seal material can be rubber, composite material, or metal. For a longer service life, a nickel-based alloy sealing ring is used in the metal sealing method.

[0063] In one embodiment, a first one-way valve 31 is provided at the front of the flexible inner tube. The two ends of the first one-way valve are connected to the inside of the flexible inner tube and the outside of the flexible outer tube, respectively. The circulating medium can flow directly from the inside of the flexible inner tube 2 to the annulus between the flexible outer tube 1 and the well wall through the first one-way valve 31, but the reverse flow will be blocked by the first one-way valve 31. This is used for circulating well washing during the running of the tubing string.

[0064] In one embodiment, a second one-way valve 32 is provided at the front of the flexible inner tube. The two ends of the second one-way valve are respectively connected to the inside of the flexible inner tube and the intermediate annulus 33. The flow direction of the second one-way valve is from the intermediate annulus 33 to the inside of the flexible inner tube. That is, during the gravel filling process, the sand-carrying liquid flows into the intermediate annulus 33 through the screen tube short section, and then flows into the flexible inner tube through the second one-way valve 32.

[0065] In one embodiment, a top suspension device 52 is provided at the rear end of the flexible outer tube. The top suspension device 52 is used to connect the flexible outer tube to the inner wall of the main well casing or the branch well window. A filling hole 34 is provided in front of the top suspension device 52. The filling hole 34 is used to inject any one or a combination of gravel, ceramsite, composite material particles, or sand into the annulus between the screen tube sub and the well wall. In cases where tubing needs to be run for production, an insertion seal is also provided behind (above) the top suspension. After the gravel filling operation is completed, the service string is pulled out and the tubing is run in. The bottom of the tubing is connected to the flexible outer tube through the insertion seal.

[0066] In one embodiment, such as Figure 3 As shown: The flexible outer tube 1 is provided with filling holes 34, several connecting short sections 11, and several screen tube short sections 12 from back to front. The flexible filling tool is lowered into the service tool, which is a gravel filling tool with a changeable flow channel. That is, the service tool includes a drill pipe 37 and a flow channel converter 36.

[0067] In another embodiment, such as Figure 4 As shown: The flexible outer tube 1 is provided with a flow channel converter 36, a filling hole 34, several connecting short sections 11 and several screen tube short sections 12 from back to front. The flexible filling tool is lowered into the service tool, which is a gravel filling tool with a changeable flow channel, that is, the service tool includes a drill pipe 37.

[0068] like Figure 7 and Figure 8 As shown, the three-dimensional well sand control tool provided by the present invention includes a top suspension device 52 and a top packer 51. For example... Figure 9 As shown, the three-dimensional well sand control tool provided by this invention can also be applied to multi-branch well conditions.

[0069] Option 2

[0070] This invention provides a method for sand control in three-dimensional wells, employing the aforementioned three-dimensional well sand control tool. The method includes:

[0071] In step S10, the fluid containing the filling material flows from back to front through the annulus formed by the flexible outer tube 1 and the well wall;

[0072] Step S20, after the fluid is filtered through the short section of the screen tube, as... Figure 5 As shown, fluid enters the flexible inner tube from the front end and flows from front to back inside the flexible inner tube.

[0073] In step S30, after the filling operation is completed, the soluble sealing plug on the wall of the flexible inner tube reaches the dissolution time, and the soluble sealing plug 22 in the tube wall through structure 21 gradually dissolves.

[0074] In step S20, the filling process includes an alpha wave phase and a beta wave phase; after filling is completed, a gel-breaking solution should be pumped in to cover the uncorrected segment.

[0075] Specifically, the fluid containing the filling material is released from the filling hole 34 and flows from back to front through the annulus between the outer tube and the well wall, with the rear end closer to the branch window and the front end farther from the branch window. Some of the fluid, after being filtered through the screen tube section, enters the annular space between the flexible outer and inner tubes and flows from back to front. Some fluid flows from back to front through the gaps in the filling material. The front end of the flexible inner tube enters the flexible inner tube, and the fluid flows from front to back inside the flexible inner tube, returning to the main wellbore through the branch well window. After filling is complete, the soluble material reaches its dissolution time.

[0076] like Figure 5 and Figure 6 As shown, the filling particles flow into the downhole from the wellhead through the flow channels inside the drill pipe 37. After passing through the flow converter 36, they are transferred from inside the service string 39 to the annular space between the flexible outer tube and the well wall, where they accumulate. Then, the filling particles flow into the annular space between the flexible outer tube and the well wall through the filling holes 34, flowing from back to front. Some of the fluid, after being filtered by the screen tube section, enters the annular space between the flexible outer tube and the flexible inner tube and flows from back to front, finally returning to the main wellbore through the flexible inner tube. The number of filling holes 34 can be 1 to 6; preferably, the multiple filling holes 34 are circumferentially distributed.

[0077] Some of the fluid flows from back to front through the gaps in the filling material and flows into the flexible outer tube through the short screen tube at the front.

[0078] The fluid enters the flexible inner tube through the second one-way valve at the front end. The fluid flows from front to back inside the flexible inner tube and returns to the main wellbore through the branch well window. After filling is completed, the filling tubing is pulled out. Then, the service tool is cleaned by positive circulation or by reverse circulation well cleaning, and the filling tubing is further removed.

[0079] The dissolution time of the soluble material is greater than the sum of the tubing operation time a and the filling time b. Once the soluble material reaches the dissolution time, it will dissolve, and the tube wall penetration structure 21 will change from a blocked state to a free-flowing state.

[0080] A wellbore includes a hole drilled from the surface or tunnel into the formation. This invention provides a method for sand control in three-dimensional wells, and can also directly employ a reverse circulation gravel packing process for well completion.

[0081] The gravel backfilling method has been described in detail above. The segmented method will be described below.

[0082] Furthermore, the screen tube short section is a pre-filled screen tube short section or a short section with a screen or screen module. The pre-filled screen tube short section includes an outer screen tube, an inner screen tube, and a filling material between the outer and inner screen tubes. The filling material is granules or wire mesh. Its function is that, in situations where injection and extraction need to be carried out in sections, the annulus in the middle is used to divide the sections, which is difficult to use for the gravel filling operation mentioned above.

[0083] The above descriptions are merely a few embodiments of the present invention. Those skilled in the art can make various modifications or variations to the embodiments of the present invention based on the content disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims

1. A three-dimensional well sand control tool, characterized in that, include: Flexible outer tube and flexible inner tube; The flexible outer tube includes a plurality of connecting short sections and screen tube short sections, or the flexible outer tube includes a plurality of screen tube short sections; The connecting short sections, the screen tube short sections, and the connecting short sections and the screen tube short sections are all connected by a universal force transmission structure, which is used to transmit torque or axial force. The flexible inner tube is inserted inside the flexible outer tube, and an intermediate annular space is formed between the flexible outer tube and the flexible inner tube; the rear part of the flexible inner tube extends to the rear of the last screen tube section; the upper part of the flexible inner tube is sealed to the flexible outer tube; the flexible inner tube remains inside the flexible outer tube after the filling operation is completed, forming a double tube structure for long-term production. Gravel can fill the annular space formed between the flexible outer tube and the well wall; The flexible outer tube has filling holes in its wall; The flexible outer tube is provided with a top suspension device at its rear end. The top suspension device is used to connect the flexible outer tube to the inner wall of the main well casing or the branch well window. The filling hole is located in front of the top suspension device, and the filling hole is used to inject filling material into the annulus between the screen tube section and the well wall; The flexible outer tube is also provided with a flow channel converter that is connected to the filling hole. The flow channel converter is connected to a service string located inside the flexible outer tube. The service string is used to connect to the drill pipe. The flexible inner tube has a tube wall through structure on its tube wall, and a soluble sealing plug is provided in the tube wall through structure. The soluble sealing plug can seal the tube wall through structure on the flexible inner tube. During gravel packing, the soluble sealing plug remains in an undissolved state. The fluid containing the packing material inside the drill pipe is transferred to the annular space between the flexible outer tube and the well wall by the flow channel converter and then flows from back to front. After being filtered by the screen tube section, the fluid enters the annular space between the flexible outer tube and the flexible inner tube and flows from back to front. It then enters the flexible inner tube from the front end and flows from front to back inside the flexible inner tube. During oil production after gravel backfilling, the soluble sealing plug dissolves to make the pipe wall through-structure conductive. The fluid in the formation is filtered by the screen pipe section and enters the annular space between the flexible outer pipe and the flexible inner pipe. The fluid then enters the flexible inner pipe through the pipe wall through-structure on the upper part of the flexible inner pipe and flows from front to back inside the flexible inner pipe.

2. The three-dimensional well sand control tool according to claim 1, characterized in that, The flexible inner tube is made of composite material, high-plasticity metal, metal wire mesh, or armored material. The length of the sieve tube short section is 1-15 times its outer diameter, and the universal force transmission structure includes a torque transmission component and a ball joint.

3. The three-dimensional well sand control tool according to claim 1, characterized in that, The integral formed by the flexible inner tube and the soluble sealing plug can withstand a pressure difference greater than 0.1 MPa between the external and internal pressures.

4. The three-dimensional well sand control tool according to claim 1, characterized in that, The soluble sealing plug is made of a soluble material, and the soluble material has a dissolution time between 10 and 1000 hours.

5. The three-dimensional well sand control tool according to claim 1, characterized in that, The fitting clearance of the universal force transmission structure is smaller than the sieving size of the short section of the screen tube, or the universal force transmission structure includes a sealing element.

6. The three-dimensional well sand control tool according to claim 1, characterized in that, A first one-way valve is provided at the front of the flexible inner tube. The two ends of the first one-way valve are respectively connected to the inside of the flexible inner tube and the outside of the flexible outer tube. The flow direction of the first one-way valve is from the inside of the flexible inner tube to the annulus between the flexible outer tube and the well wall.

7. The three-dimensional well sand control tool according to claim 1, characterized in that, A second one-way valve is provided at the front of the flexible inner tube. The two ends of the second one-way valve are respectively connected to the inside of the flexible inner tube and the intermediate annulus. The flow direction of the second one-way valve is from the intermediate annulus to the inside of the flexible inner tube.

8. A method for sand control in three-dimensional wells, characterized in that, The sand control tool for three-dimensional wells according to any one of claims 1-7, wherein the sand control method comprises: Fluid containing filling material flows from back to front through the annulus formed by the flexible outer tube and the well wall; After being filtered by the short section of the screen tube, the fluid enters the flexible inner tube from the front end and flows from front to back inside the flexible inner tube. After filling is completed, the soluble sealing plug on the wall of the flexible inner tube reaches the dissolution time, which is 10-1000 hours.

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